1. Dimensioning A dimensioned drawing should provide all the information necessary for a finished product or part to be manufactured. An example dimension is shown below. Dimensions are always drawn using continuous thin lines. Two projection lines indicate where the dimension starts and finishes. Projection lines do not touch the object and are drawn perpendicular to the element you are dimensioning. All dimensions less than 1 should have a leading zero. i.e. .35 should be written as 0.35

2. Types of Dimensioning • Parallel Dimensioning • Parallel dimensioning consists of several dimensions originating from one projection line.

3. Superimposed Running Dimensions • Superimposed running dimensioning simplifies parallel dimensions in order to reduce the space used on a drawing. The common origin for the dimension lines is indicated by a small circle at the intersection of the first dimension and the projection line.

4. Chain Dimensioning • Combined Dimensions • A combined dimension uses both chain and parallel dimensioning.

5. Dimensioning of circles • (a) shows two common methods of dimensioning a circle. One method dimensions the circle between two lines projected from two diametrically opposite points. The second method dimensions the circle internally. • (b) is used when the circle is too small for the dimension to be easily read if it was placed inside the circle.

6. Dimensioning Radii • All radial dimensions are proceeded by the capital R. • shows a radius dimensioned with the centre of the radius located on the drawing. • (b) shows how to dimension radii which do not need their centres locating.